Generally, an outdoor stadium such as a baseball field, a football field, sports complex and the like has lighting towers. The light tower is required to produce a relatively high output to light a playing field during a match, and consumes substantial amounts of electric power. Recently, technologies using LED lighting have been developed to reduce electric power consumption for the lighting of playing fields or similar areas.
A recently developed device in the related art includes a floodlight for a playing field that uses an LED lamp. The LED floodlight has a structure with a lens assembled with each LED. However, although an LED chip of about 1 watt is used for a high power LED lighting device requiring an output equal to or greater than about 800 watts, at least 840 LED chips must be used in the LED lighting device in consideration of a loss of light. Accordingly, the time required to couple a lens to each LED substantially increases which thus decreases productivity.
Further, a structure of adjusting an angle of the floodlight was developed, in which an angle of the floodlight is adjusted upwardly and downwardly and then a hinge is tightened and secured by a bolt. However, a coupling force acts on the floodlight to change the adjusted angle of the floodlight when the bolt is tightened, resulting in a deviation from a desired angle change.
In addition, although a high power LED lighting device is designed considering a weight and a volume of the LED lighting device, generally, the high power LED lighting device usually has a predetermined area since it is substituted for a conventional lighting device instead of being built specifically for an LED lighting device. As described above, at least 840 LED chips must be used to implement the high power LED lighting device with a capability of about 800 watts, and a reflector must protrude at a sufficient height from a light emitting surface of the LED chips to reflect lights emitted from all LED chips to form a desired light distribution. This causes an increase in weight and volume of the high power LED lighting device.